Developing Virtual Reality-Based Exposure for Adults with Social Anxiety Disorder

Introduction
SAD is characterized by the Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.; DSM-V-TR) as: “A marked and persistent fear of one or more social or performance situations in which the person is exposed to unfamiliar people or to possible scrutiny by others (American Psychiatric Association, 2022).” SAD is often associated with biological symptoms such as increased heart rate and sweat response. SAD is one of the most prevalent anxiety disorders in the world, especially in western cultures, with a lifetime prevalence of between 4% and 12%. Further, a diagnosis of SAD increases the risk of developing comorbid disorders severely. SAD often occurs earlier than comorbid disorders and has been pointed to as a predictor of disorders such as majordepressive disorder and alcohol use disorder. SAD is most commonly treated using a combination of cognitive behavioral therapy (CBT) and psychopharmacological treatment. While this treatment is effective, many individuals refrain from seeking treatment or drop out when faced with exposure; a crucial component of CBT in which one faces anxiety-provoking situations.

VR8 is a large Danish VR-trial conducted at Center for Digital Psychiatry in the Region of Southern Denmark in 2019-2024 that aimed to develop, evaluate and assess the effect of 360-degrees videos with exposure content and biofeedback (heart rate and skin conductance levels) for adults with SAD. This thesis consists of two studies (and two articles) that are part of VR8 and ran at the beginning of the trial. First, a systematic review of the use of biomarkers in anxiety disorders and second a mixed methods study exploring the feasibility of the developed VR content.

Aims
The first aim of this thesis was to conduct a systematic review that investigated how biomarkers(such as heart rate and skin conductance levels) can be utilized in virtual reality-based exposure foranxiety.

The second aim was to develop and assess the feasibility of VR-based exposure as an alternative toin vivo exposure for SAD by investigating three key aspects: anxiety, relevance and usability.

Based on these studies the thesis aimed to summarize, compare, contrast and discuss the findings asthey relate to the overall scientific field of virtual reality-based exposure for anxiety disorders and SAD specifically. Finally, clinical implications and future considerations for use of virtual reality-based exposure are discussed.

Methods
First, the systematic review was conducted, which aimed to investigate the current literature addressing the use of biomarkers in virtual reality-based exposure (VR-Exp) in treatment of anxiety in adults. Specifically, we sought to investigate the use of biomarkers in VR-Exp and their synchrony with self-reported anxiety scores.

Next, a feasibility study was conducted to investigate the feasibility of the developed virtualreality-based exposure by investigating the following questions:

- Are the 360 degrees virtual environments able to evoke anxiety responses in SAD participants?

- Are the virtual environments relevant to patients with SAD?

- Are the VR exposures perceived as a useful alternative to exposure in vivo?

We used a design involving participants with SAD (n=10) recruited from outpatient psychiatric treatment in the Psychiatry in the Region of Southern Denmark. Further a control group (n=10) was recruited for comparison of quantitative measurements. Quantitative findings related to anxiety, presence and usability were then compared to qualitative results comprised of themes derived from a general inductive approach analysis.

Results

Results from the systematic review identified heart rate as a promising biomarker, showing tentative efficacy in identifying changes within and between sessions in the majority of instances. However, the synchrony between overall biomarker findings and questionnaire results was inconclusive. Notably, skin conductance level demonstrated high synchrony for differences between groups, indicating its potential as a reliable biomarker for group distinctions. Further, limitations such as biosensor sensitivity to movement may have influenced the results.

Results from the feasibility study indicated that participants with SAD experienced higher anxiety in the virtual environments (VE) compared to controls. Although anxiety levels were consistently higher in the SAD group, significant differences when adjusting for baseline anxiety scores were observed in only two out of four environments. Furthermore, while both groups reported acceptable presence scores, individuals with SAD scored significantly lower than the control group. Finally, both groups provided acceptable usability scores, however, the control group scored a category higher on usability than the SAD group.

Discussion

The systematic review highlighted the prevalence of heart rate and skin conductance level as the primary biomarkers utilized in VR-Exp for anxiety disorders, particularly in studies targeting specific phobias. While these biomarkers demonstrated moderate success in discerning differences between groups and changes between sessions, challenges such as individual biomarker variability and novelty sensitivity were noted, highlighting the necessity for further research in this domain. 

The feasibility study of a 360 degrees virtual reality exposure tool within the VR8 project showcased promising results for its application in clinical settings. Participants with SAD exhibited heightened anxiety across various virtual environments, with optimal anxiety induction observed when participants were fully engaged in task-oriented environments. The VR-Exp was deemed a valuable alternative to exposure in vivo, receiving acceptable usability scores from both SAD patients and controls. The potential of VR-Exp as an effective tool for anxiety disorders is promising. However, it is important to emphasize technological and methodological challenges for its successful implementation in clinical practice.

Conclusion

The thesis explored the utilization of virtual reality-based exposure therapy for anxiety disorders. The first study conducted a systematic review on the use of physiological markers in virtual reality-based exposure therapy, finding heart rate and skin conductance level as commonly employed biomarkers. Specific phobias were the most studied disorders, and while biomarkers showed moderate success, challenges such as individual variability were noted. The second study assessed the feasibility of a 360 degrees virtual reality-based exposure tool for social anxiety disorder within the VR8 project. The tool included four virtual environments and was deemed feasible for clinical use, inducing anxiety effectively, particularly when participants were fully engaged. Both studies suggest virtual reality as a promising alternative for exposure therapy, though further research is warranted to further optimize its effectiveness. The findings are compared and contrasted with current research, and call for further investigation into the underlying mechanisms in virtual reality-based exposure, including clinical implications of environment development, medium choice, presence and social interaction in virtual environments.